Bamboo zephyr board

ABSTRACT

Two types of synthetic resin are used with zephyrs  2  made from a wide range of bamboo canes from undried to dried. An appropriate amount of special thread  4  comprising a core thread  5  having a high melting point and a core-thread covering skin  6  having a low melting point are added to the zephyrs and kneaded together. When molding the kneaded material, it is heated to the temperature at which the skin starts to melt and pressed. Then the skin works as a binder that binds the zephyrs and the core thread. The core thread supplements the strength and the flexibility of the bamboo zephyr board.

FIELD OF THE INVENTION

[0001] The present invention relates to a bamboo zephyr board made bykneading continuous mesh fiber bamboo zephyrs into a board having aninfinite number of gaps inside.

BACKGROUND OF THE INVENTION

[0002] Wood has a long history during which abundant techniques forprocessing wood have been developed. Some of these techniques have ledto the development of new materials. These materials are divided intothose taking advantage of the wood's original shape and those that haveno relation with the wood's shape. The former type includes squaretimbers, boards and laminated boards, while the latter type includescompressed boards called particle boards or M.D.F boards, which are madeby compressing chips by grinding, cutting and bonding, and cementedexcelsior boards.

[0003] Wood has been used in various forms of building materials. Butthe wood's poor reproducibility has always been a cause for its shortsupply and increased cost. In search of low cost building materials,bamboo, which previously had limited uses despite their goodreproducibility, have begun to be used as alternative building materialsthanks also to advances in production technology, which made it possibleto process round bamboo canes into flat plates.

[0004] Although bamboo is superior to wood in terms of reproducibility,most bamboo materials have a hollow cross sectional shape and a diameterand a length that are shorter than wood materials. Many bamboo materialsare also curved, which is a negative factor when viewed as buildingmaterials. Large-diameter portions of long bamboo canes are usable asbuilding materials because they can be developed flat. But the remainingportions of such canes and many other smaller bamboo canes are notadequate as building materials, and have limited applications.

[0005] Bamboo has excellent reproducibility because it normally takesonly three to five years before it can be used a building material andhas hardness and a beautiful grain of fibers. As mentioned above,however, a large portion of a bamboo cane is discarded without beingused. Therefore, producing a building material comparable to woodproducts using bamboo stems, branches and leaves is a challenge that canlead to an effective use of resources.

SUMMARY OF THE INVENTION

[0006] The objective of the present invention is to make effective useof bamboo stems, branches and leaves, thereby to solve theabove-mentioned problems by providing a bamboo zephyr board.

[0007] In one aspect, the present invention is a bamboo zephyr boardusing a zephyr taken from a range of undried to near undried bamboocanes of an appropriate length, characterized in that the zephyrs arekneaded and pressed while being heated at a temperature at whichvascular bundle ingredients contained in bamboo ooze out to the surfaceand, using the extract of the bamboo as a binder that binds the zephyrs,formed into a board of a certain shape, equipped with an infinite numberof gaps inside.

[0008] In another aspect, the present invention is also a bamboo zephyrboard using a zephyr taken from a range of undried to dried bamboo canesof an appropriate length, characterized in that the zephyrs are kneadedafter being added with an appropriate amount of synthetic resin fiberthread that melts at a desired heating temperature and, using the moltenthread as a binder that binds the zephyrs, pressed and formed into aboard of a certain shape equipped with an infinite number of gapsinside.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention uses zephyrs (i.e. continuous mesh fiber)taken from an appropriate length of a bamboo cane or a combination ofsuch zephyrs and chips. The zephyrs are kneaded and crossed at randomuntil they form a mass of an appropriate size. The zephyrs are thenpressed and heated, and glued using the ingredients of the zephyrsthemselves or with a synthetic resin fiber thread or with an adhesive.In this way, the zephyrs are made into a board of an appropriate sizehaving an infinite number of gaps inside.

[0010] The zephyrs are made from a range of undried to dried bamboocanes stripped of joint ridges and joint disks. Continuous mesh fiberscan be collected by rolling a long bamboo cane with a grooved roller,but this method requires the cutting process afterwards. By using shortcanes selected from the range of 10 to 100 mm, or more preferably, 10 to70 mm, and processing them with a crusher, short fibers can be obtaineddirectly. These zephyrs are agitated and mixed so that the fibers arecrossed randomly. The zephyrs are then heated by way of indirect heatingusing steam and hot air or by way of direct heating using high-frequencywave and microwave and made into an appropriate shape.

[0011] When producing zephyrs from a range of undried to near undriedbamboo canes, vascular bundle ingredients such as hemi-cellulose andlignin ooze out to the surface because of the heat. These ingredientswork as a binder. Therefore, the zephyrs can be made into a boardwithout using any adhesive. By varying the amount of and pressureapplied to the zephyrs, a variety of boards ranging from those havingthe hardness and density of particle boards or M.D.F boards, which aremade by compressing wood chips, to those having the hardness and densityof glass wool, which is a non-compressed thermal insulating material.

[0012] When producing zephyrs from a range of dried to near dried bamboocanes, the ingredients are not expected to ooze out much even whenheated. Therefore, when kneading zephyrs, a synthetic resin fiber threadthat melts at an appropriate heating temperature is selected and addedin a volume ratio of 5-50%, preferably 5-20%. Then the thread melted byheat works as a binder, which binds the zephyrs when they are pressedinto a board shape. A polyethylene thread, for example, melts at arelatively low temperature.

[0013] While a thread made of a single material may melt and work as abinder, a special-thread made of at least two kinds of synthetic resin,for example, a material with a high melting point for the core and amaterial with a low melting point for the skin that covers the core, canproduce an effect that cannot be obtained by a thread made of a singlematerial. In this case, the thread made of two kinds of synthetic resinis heated at the temperature at which the skin starts to melt. Then theskin works as a binder that binds the zephyrs with the core of thethread, which supplements the strength and flexibility of the board. Forexample, in the case of a special thread having the core made ofpolypropylene and the skin made of polyethylene, polypropylene meltsfirst.

[0014] To form the zephyrs into a certain form after kneading, a splitdie is used. An appropriate pattern is formed so as to project on thesurface of the split die. When the zephyrs are put in this die andheated and pressed, a zephyr board is formed with the pattern on itssurface. In this way, a zephyr board having a multitude of dimples orthrough holes, for example, can be made easily. The only thing thatneeds to be taken into consideration when making such a pattern is thatit is easy to take it off after the board is molded. Therefore, avariety of patterns can be formed. When zephyrs are taken from bamboocanes, the boards become white. If desired, they may be colored bypigment coating.

[0015] Wood chips or a combination of wood chips and chips of bamboobranches and leaves having a volume that is 10 to 50%, preferably 10 to30%, of the volume of the zephyrs can be mixed to make a wood and bambooboard. Using a synthetic fiber thread in the abovementioned volume ratioas a binder and heat them till the fiber is melt, or by adding a powderor liquid adhesive in the volume ratio of 1 to 20%, preferably 10 to15%, and heating them till the powder is melt or the liquid issolidified, a decorative plate having dispersed leaves and branches isobtained. The leaves change their color depending on the heatingtemperature. It is also possible to impart smell adsorptive capabilityto the board by adding bamboo powder to the chips of bamboo branches andleaves.

[0016] As a powder adhesive, styrene, ester, or polyamide family may beused. As a liquid adhesive, urethane family may be used. Apart from thebinder, it is preferable to add a powder having water-holding power inthe volume ratio of 0.5 to 10% to obtain a final product havingwater-holding power. As a water-holding powder, anionic substances maybe used.

[0017] To enhance the water-holding power, it is preferable to applydiatomaceous earth to the surface of the zephyr boards. To enhance theappearance, it is preferable to apply a powder made from crushed shellsto the surface of the zephyr boards.

[0018] As explained above, a zephyr board made entirely or mostly ofbamboo has applications for its elasticity, thermal insulation, soundinsulation and shock absorbing capability. After they finish theirlives, they can be crushed and recycled, causing less strain on theenvironment. The characteristics of these zephyr boards are not found inother kinds of building materials.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features and advantages of the invention will appear as thedescription proceeds when considered in conjunction with theaccompanying drawings, in which:

[0020]FIG. 1(A) is a side view of the zephyr board of Example 1, while

[0021]FIG. 1(B) is an enlarged view of a portion of its model.

[0022]FIG. 2(A) shows a condition in which the special thread made ofsynthetic resin of Example 3 and zephyrs are adhered. FIG. 2(B) is anenlarged model of a portion of the special thread.

[0023]FIG. 3 shows a process of making the bamboo zephyr board havingthrough holes of Example 4.

[0024]FIG. 4 shows a bamboo zephyr board having a diatomaceous earthsurface.

EXAMPLE 1

[0025]FIG. 1(A) is a view of the side of a zephyr board. FIG. 1(B) is anenlarged view of a portion of a plan view of the same zephyr board. Tomake the zephyrs 2 of FIG. (B), a long bamboo cane was roll-pressed by aroller to zephyrize the cane and cut into zephyrs of an appropriatelength. Alternatively, a bamboo cane may be cut into rings first, andthen further split into narrow pieces and crushed in a crusher to makemesh fibers. In the former method, it is easy to produce zephyr fibersof a uniform diameter and length, but in the latter method, it isdifficult to standardize the diameter and length. It should also beconsidered, however, that excessively long fibers are difficult to bekneaded, and that crushers are usually cheaper than rollers.

[0026] Zephyr board 1 uses zephyrs 2 obtained from a range of undried tonear undried bamboo canes. When the zephyrs were heated and molded in adie, the heat caused the ingredients of the zephyrs to be extracted.These ingredients worked as a binder that binds the zephyrs, thereforeno other adhesives were necessary. By adjusting the amount of zephyrs 2and the pressure that was applied to them, different specifications ofzephyr board having different degrees of hardness and density but havingthe same size was obtained. Because the fibers cross with each other andcreate an infinite number of gaps 3, zephyr board 1 has elasticity,thermal insulation, sound insulation and a shock-absorbing capability.It is also possible to vary the levels of such capabilities according tothe applications.

EXAMPLE 2

[0027] By adding a polyethylene thread having a volume corresponding to15% of the volume of the zephyrs and kneading it with the zephyrs, thepolyethylene melted and worked as a binder that binds the zephyrs. Inthis way, a zephyr board was made by pressure, and without adding anyadhesive. While polyethylene is easy to use because it melts at a lowtemperature, it is easily deformed when heated. Therefore, this methodis not expected to add strength or flexibility to the board. Thecapabilities obtained from this example were the same as those inExample 1 (see FIG. 1).

EXAMPLE 3

[0028]FIG. 2(A) is an enlarged cross sectional model of a portion of azephyr board made by mixing zephyrs 2 and a special thread 4 comprisinga polypropylene core thread 5 and a polyethylene skin 6 in a volumeratio of 100 to 15. When producing this board in a die, etc., it washeated at a temperature at which only the skin melts. Then the moltenskin formed a node 7 that worked as a binder between the zephyr and thecore thread. The core thread supplements the strength and flexibility ofthe board.

[0029] In this configuration, zephyrs 2 produced from a range of undriedto dried bamboo canes were used. No adhesive was necessary as in thecase of a particle board, which was made by gluing chips with adhesive.By adjusting the amount of zephyrs and pressure, various zephyr boardshaving the same size but varying degrees of hardness and density weremade. Fibers crossing inside the board form an infinite number of gaps,which provide the same capabilities as in Examples 1 and 2.

EXAMPLE 4

[0030]FIG. 3 shows a cross section of a bamboo zephyr board 8 havingthrough holes. This board was made by using split dies 9, 10 that wereused in the manufacturing process of the zephyr boards of Examples 1 and2. Projections extend from one die to the other. The dies were heatedand pressed to make the bamboo zephyr board 8 having through holes.Instead of the holes, the board may be given dimples. To make such aboard, dies having short projects are used. As long as the dies areeasily taken off the board, the projections may of any shape. Byadjusting the amount of zephyrs 2 and pressure applied, various zephyrboards having the same size but varying degrees of hardness and densitywere made as in the other examples.

EXAMPLE 5

[0031] Chips of bamboo leaves and branches were added to the zephyrs 2in a volume ratio of 10%. As a binder, powder adhesive was used. Theywere kneaded, heated and pressed to make a zephyr board 1 similar to theone shown in FIG. 1, or a zephyr board 8 having through holes similar tothe one shown in FIG. 3. The surface of the board has a pattern of thedotted leaves and branches.

EXAMPLE 6

[0032]FIG. 4 shows a bamboo zephyr board 11 having a diatomaceous earthsurface 12. The board itself has no limitation of its ingredients andadhesives.

[0033] In the drawings and specification, there has been set forthpreferred examples of the invention, and although specific terms areemployed, they are used in a generic and descriptive sense only and notfor the purpose of limitation, the scope of the invention being setforth in the following claims.

1. A bamboo zephyr board comprising zephyrs taken from a range ofundried to near undried bamboo canes of an appropriate length, saidzephyrs being kneaded and pressed while being heated at a temperature atwhich vascular bundle ingredients contained in bamboo ooze out to thesurface, said extract of the bamboo being used as a binder that bindsthe zephyrs, thereby said zephyrs are formed into a board of a certainshape equipped with an infinite number of gaps inside.
 2. A bamboozephyr board comprising zephyrs taken from a range of undried to driedbamboo canes of an appropriate length, said zephyrs being kneaded afterbeing added with an appropriate amount of synthetic resin fiber threadthat melts at a desired heating temperature, said molten thread beingused as a binder that binds the zephyrs, thereby said zephyrs and moltenthread are pressed and formed into a board of a certain shape equippedwith an infinite number of gaps inside.
 3. A bamboo zephyr boardaccording to claim 2, wherein the synthetic resin fiber thread thatmelts at a desired temperature is a special thread comprising a corethread made of synthetic resin of a high melting point and an externalskin, which covers the periphery of the core thread, made of syntheticresin of a low melting point, and when the synthetic resin fiber threadis heated to a temperature at which the skin melts, the molten skinworks as a binder that glues the zephyrs and the core thread work as asupplemental material that provides strength and flexibility to thebamboo zephyr board.
 4. A bamboo zephyr board comprising zephyrs andchips taken from a range of undried to near undried bamboo, said zephyrsand chips being kneaded together with an adhesive and pressed whilebeing heated, said zephyrs, chips and adhesive are formed into a boardof a certain shape equipped with an infinite number of gaps inside.
 5. Abamboo zephyr board according to claim 4, wherein the chips are takenfrom crushed bamboo leaves and branches.
 6. A bamboo zephyr boardaccording to claim 1, wherein a water-holding powder is added.
 7. Abamboo zephyr board according to claim 1, wherein when the zephyrs areformed into a board of a certain shape, a multitude of dimples orthrough holes are formed simultaneously on the up side and down side ofthe zephyr board.
 8. A bamboo zephyr board according to claim 1, whereindiatomaceous earth is applied to the surface thereof.
 9. A bamboo zephyrboard according to claim 1, wherein shell powder is applied to thesurface thereof.